Known examples of such a safety valve include a safety valve provided with a fusible material configured to fuse at the time of high temperature and configured to release gas in a container by a movement of a movable plug body in association with fusion of the fusible material (PTL 1).
An example of a safety valve of the related art is illustrated in FIG. 3.
This safety valve (41) of the related art includes: a cylindrical housing (42) provided with a fusible alloy (fusible material) (11), a movable body (43) configured to move in association with fusion of the fusible alloy (11) and a compression coil spring (13) configured to urge the movable body (43) toward the fusible alloy (11); a main body (3) fixed to a right end portion of the housing (42) and extending downward; a movable plug body (4) arranged in a movable plug body arrangement passage (5) in the main body (3) so that an upper end portion thereof projects inward of the housing (42) and configured to move in association of a movement of the movable body (43); and a relief passage (6) communicating with the movable plug body arrangement passage (5) and configured to be opened by the movement of the movable plug body (4).
The safety valve (41) is used with the main body (3) thereof mounted on a container and, for example, a fire occurs and the temperature rises, the fusible alloy (11) fuses at a predetermined temperature and, accordingly, the movable body (43) urged leftward by the compression coil spring (13) moves leftward, and accordingly, the movable plug body (4) is allowed to move and is moved upward by an internal container pressure, whereby gas in the container is discharged through the movable plug body arrangement passage (5) and the relief passage (6) of the main body (3).
With the safety valve (41) of the related art, a discharge port (44) of the fused fusible alloy (11) is provided so as to penetrate through a peripheral wall (42a) of the housing (42), and the fused fusible alloy (11) passes through the discharge port (44) and discharged to the outside of the housing (42).
PTL 1: JP-A-2008-202736